Create a preferences page accessible directly by url

The only preference so far is diverting production analytics.
Use trackLiveAnalytics, not trackAnalytics, for clarity

Users are not turning off analytics completely, just sending them to
the sandbox rather than production analytics project on segment.io.
This helps make that more clear.
Merge pull request #161 from andrew-polk/feature/prefsPage

Create a preferences page accessible directly by url